Seismic hazard analysis for central-western Argentina

Abstract

In this study, we present a PSHA (Probabilistic Seismic Hazard Analysis) for the city of San Juan, which is located in the central-western region of Argentina (30°S–35.5°S; 66.5°W–71°W). In addition to crustal earthquakes provided by catalogues, recent paleoseismological and neotectonic investigations have permitted to consider events which occurred during the last 400 years. Four seismogenic sources that could cause damages to the studied site corresponding to Precordillera, Western Sierras Pampeanas, Basement of the Cuyana Basin and Cordillera Principal were identified. Based on the evaluation of the contribution of these sources, maximum moment magnitudes above 7.5 (Mw) are expected. High values of SA (spectral acceleration) (0.2 and 1 s periods) and PGA (peak ground acceleration) were found in the city of San Juan, which suggests that it is located in a zone of high seismic hazard. Finally, the obtained SA spectra were compared with the seismic-resistant construction standards of Argentina INPRES-CIRSOC 103 [1]. Results suggest that for the city of San Juan and for a return period of 475 years, it covers the seismic requirements of the structures.